The country is bounded on the west by Thailand, on the north by Laos, in the east by Vietnam and to the south by the Gulf of Thailand and is about half the size of Italy. Topographically, the country is dominated by the mighty Mekong River, which cuts through the country from north to south; the Tonlé Sap (Great Lake); the Elephant and Cardamom mountains in the southwest; the Dangkrek Mountains along the Thai border; and the Eastern Highlands in the northeast. The most densely populated areas lie on the fertile central plains of the Mekong-Tonlé basin.